Motor boat drive



Patented June 2, 1931 UNITED STATES CHARLES N. COLSTAD, F ATTLEB ORO, MASSACHUSETTS MOTOR BOAT DRIVE Application'filed August 1, 1930. Serial No. 472,405.

My present invention relates to motor boats, and more particularly to a novel engine driving unit therefor.

An object of the invention is the provision of 'a motor boat in which the power plant is an inboard motor operating the propeller on the outboard motor principle.

Another object. of the invention resides in the provision of means to take up and absorb '10 thrust, vibration, whipping, and shocks and blows imparted to the external gear casing or propeller, without injury to the hullof the boat itself.

In carrying out my invention I preferably utilize a vertical drive shaft or crank shaft, driving the propeller through the medium of beveled gears and a horizontal propeller shaft. The engine utilized may be either of the type with a vertically arranged crank 2 shaft, or of the type having a horizontal crank shaft.

' The beveled gears referred to are housed in a gear casing externally of and below the hull of the boat, and interposed between said gear casing and the keel of the boat is a drive strut preferably provided with a horizontal projecting flange for engagement with the keel. The drive strut is provided with a vertical tube which projects through the keel and into the barrel of a bed plate flange which is fixed to the engine bed, although said barrel may constitute a part of the crank case if desired. The drive strut tube has a rela tively tight fit with the bed plate flange barrel, and the vertical crank or drive shaft depends through said tube and said strut into the external gear casing or gear box. The drive strut is fixed to the keel of the boat by tie-rods which simply serve the purpose of tying the strut to the keel, these tierods taking no driving strain. Thus any shocks or blows transmitted to the external gear box or strut will be taken by the bed plate flange through the medium of theidri've strut tube. Suitable frame members are preferably interposed between the engine bed and the keel so that that portion of the boat surrounding the drive strut tube is substantially box-shaped for greatest strength.

By reason of my novel construction I am enabled to dispense with any external skegs or other reenforcing or shock receiving devices.

When utilizing a conventional inboard motor, but with the vertical driving shaft above referred to, a far more simple installation and construction is provided than with the conventionallong propeller shaft, strut, skegs, and the like. W'hen utilizing this latter form of the invention, the bed plate I flange is constructed as a gear box to enclose the beveled gears transmitting torque from the engine crank shaft to the vertical drive shaft, the construction being otherwise identical with the construction utilized with the vertical crank shaft. 1

Other features and objects of the invention reside in the particular construction and arrangement of my novel driving unit, and

said objects and features, details of construcan enlarged scale, illustrating the drive strut o and assembly; and

Fig. 3 is a fragmentary longitudinal sectional view illustrating the invention adapted to a power plant with a horizontal drive shaft.

Referring now to Figs. 1 and 2, respresenting the preferred embodiment of the invention, 1 designates power head or engine which may be of any type operating a vertical crank shaft 2. This engine is mounted on a bed plate flange 3 which is in turn seated on the engine bed 4, said engine bed having a hole therethrough, through which the barrel 5 of the flange 3 projects, studs 6 also projecting through suitable holes in the engine bed 4, said studs being fixed to the crank case of the engine 1, and nuts 7 securely uniting the engine 1 and flange 3 to the bed 4. The engine bed 4 is spacedabove the keel 8, and laterally extending frames 9" are inall:

terposed between the bed i and keel 8, for strength and rigidity. The barrel 5 may be formed as a part of the engine crank case if desired, instead of being formed on the flange 3.

Fixed to the lower end of the crank shaft 2 is a beveled gear meshing with a beveled gear 11 on the propeller shaft 12, these gears and the lower end of the crank shaft 2 being housed in a gear boX or casing 13. The gear box 13 is spaced below the keel 8 drive strut 1% having a horizontal flange 15 in engagement with the underside of the keel 8. Preferably integral with the strut 1% is a vertically projecting tube 16 which extends upwardly through the keel 8 and into the bar rel 5 of the flange 3, having a close lit in said barrel. Studs 17 are fixed in the casing 13 and project upwardly through the keel 8, nuts 18 being fixed to the upper end of said studs to unite and clamp the strut 14: between the casing 13 and keel 8. The studs 1'? are simply tie-rods, and function in this capacity only, these studs taking no driving strain whatei'er. By removing the nuts 18 from the tie-rods 17, the strut 1% with its tube 16, casing 13 and crank shaft 2 can be pulled downwardly as a unit, DTP-f the boat.

No vibration whatever 11; ansmitted from the propeller or casing 13 to the hull of the boat, all such vibration being absorbed through the extension tube 16 of the strut 14. and the barrel 5 and bed plate flange 3. The tube 16 and barrel 5 will also withstand and absorb shocks or blows received by the casing 13, its nose 19, or the propeller 20. Thus no protecting or reenforcing skegs between the casing 13 and keel 8 are required, because of the inherent strength of my novel construction. The engine bed 4. preierably consists merely of a plank or beam of sufficient width to accommodate the engine, it not being essential to utilize an engine bed extending the entire width of the boat.

I believe that the boat construction and driving unit above briefly described is novel and I have, therefore, claimed the same broadly in the present invention.

In Fig. 3 I have illustrated a modification of power plant, wherein an engine 21 with horizontal crank shaft 22 is utilized. The engine 21 is mounted on the engine bed 4, and for the bed plate flange 3 is substituted a twopart gear box 23 adapted to constitute a bearing for one end of the crank shaft and to house the beveled gear on said .rank shaft, as well the beveled gear 25 fixed to the upper end of the vertical drive shaft 26. The gear box 23 has a barrel 2'? similar to the barrel 5 and for the same purpose, that is, to accommodate the upper end of the tube 16. Bolts 28 unite the gear box 23 to the engine bed 4-, and otherwise the construction of my novel boat is identical with that illustrated in Figs. 1 and 2.

This provides a simple and cfiicient installation for the conventional inboard motor, and is more satisfactory than driving a long propeller shaft through the usual conventional designed struts, skegs, or other devices.

I believe that the structure illustrated in Fig. 3 is well within the range of my present invention, and have, therefore, included claims to this construction in the present application.

lVhile I have necessarily described the present invention somewhat in detail, it will be appreciated that I may vary the size, shape, and arrangement of parts within reasonably wide limits without oeparting from the spirit of the invention.

My invention is further described and defined in the form of claims as follows:

1. Motor boat construction of the kind described, comprising a keel, an engine bed spaced from said keel, an engine, a vertical drive shaft, a strut fixed to the under surface of said keel, and a vertical tube projecting upwardly from said strut through said keel and into said engine bed.

2. Motor boat construction of the kind described, comprising a keel, an engine bed spaced from said keel, an engine, a vertical drive shaft, a barrel fixed in said bed, a strut fixed to the under surface of said keel, and a vertical tube projecting upwardly from said strut through said keel and into said barrel.

3. Motor boat construction of the kind described, comprising a keel, an engine bed spaced from said keel, an engine, a vertical drive shaft, a barrel fixed in said bed, a strut fixed to the under surface of said keel, a vertical tube projecting upwardly from said strut through said keel and into said barrel, and a horizontal flange around the top of said strut in engagement with said keel.

4. Motor boat construction of the kind described, comprising a keel, an engine bed spaced from said keel, an engine, a vertical drive shaft, a barrel fixed in said bed, a strut fixed to the under surface of said keel, a vertical tube projecting upwardly from said strut through said keel and into said barrel, a gear casing mounted below said strut, and a vertical driving shaft depending through said tube and said strut and projecting into said casing.

5. Motor boat construction of the kind described, comprising a keel, an engine bed spaced from said keel, an engine, a vertical drive shaft, a barrel fixed in said bed, a strut fixed to the under surface of said keel, a vertical tube projecting upwardly from said strut through said keel and into said barrel, a gear casing mounted below said strut, a vertical driving shaft depending through said tube and said strut and projecting into said casing, and means to secure said strut and said casing to said keel.

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6. Motor boat construction of the kind described, comprising a keel, an engine bed spaced from said keel, an engine, a vertical drive shaft, a barrel fixed in said bed, a strut fixed to the under surface of said keel, a vertical tube projecting upwardly from said strut through said keel and into said barrel, a gear casing mounted below said strut, a vertical driving shaft depending through said tube and said strut and projecting into said casing, and means to secure said strut and said casing to said keel, said casing, said strut, tube and vertical shaft being removable as a unit.

7. Motor boat construction of the kind described, comprising a keel, an engine bed spaced from said keel, an engine, a vertical drive shaft, a barrel fixed in said bed, a strut fixed to the under surface of said keel, a vertical tube projecting upwardly from said strut through said keel and into said barrel, a gear casing mounted below said strut, a vertical driving shaft depending through said tube and said strut and projecting into said casing, means to secure said strut and said casing to said keel, said casing, said strut, tube and vertical shaft being removable as a unit, a gear box mounted on said engine bed, a beveled gear fixed to the upper end of said vertical shaft, a beveled gear in mesh with said first beveled gear, said second beveled gear being fixed to a substantially horizontal engine crank shaft, said beveled gears being housed in said gear boX, and said gear box constituting a bearing for one end of said crank shaft.

8. Motor boat construction of the kind described, comprising a keel, an engine bed spaced from said keel, an engine, a vertical drive shaft, a barrel fixed in said bed, a strut fixed to the under surface of said keel, a vertical tube projecting upwardly from said strut through said keel and into said barrel, a gear casing mounted below said strut, a vertical driving shaft depending through said tube and said strut and projecting into said casing, means to secure said strut and said casing to said keel, said casing, said strut, tube and vertical shaft being removable as a unit, a gear box mounted on said engine bed and integral with said barrel, a beveled gear fixed to the upper end of said vertical shaft, a beveled gear in mesh with said first beveled gear, said second beveled gear being fixed to a substantially horizontal engine crank shaft, said beveled gears being housed in said gear box, and said gear box constituting a bearing for one end of said crank shaft.

In testimony whereof, I have signed my name to this specification.

CHARLES N. COLSTAD. 

